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‘Anti-laser’ built for first time

AN ANTI-LASER – which absorbs light rather than emitting it – has been built for the first time.

A laser shines by producing a cascade of photons that bounce around inside a light-amplifying material before exiting from one or both ends. In 2010, Douglas Stone at Yale University and colleagues devised a way to reverse the process, with a material that absorbs rather than amplifies light.

The researchers calculated that if they used a light-absorbing material like silicon, then at certain wavelengths, two identical laser beams shone directly at each other would cancel out inside the material.